On
the night of August 6-7, 1952, Will Jansen, a marine engineer
and designer, was visiting in Kerkrade, Holland. Just
after midnight a disc-shaped craft with visible superstructure
swooped down to low altitude, hovered, zigzagged and sped
away. A second disc-shaped UFO, similar in outline, was
then seen hovering farther away. Finally it tilted up
vertically and shot up out of sight.

First of two discs observed by Will Jansen. "Cabin"
protruded from
underside too on second UFO. (credit: NICAP/Hall)

Source:
NICAP/Richard Hall, 1964 (from letter to CSI of Los Angeles)

On
the night of August 6-7, 1952, Will Jansen, a marine engineer
and designer, was visiting in Kerkrade, Holland. Just
after midnight, a disc-shaped craft with visible superstructure
swooped down to low altitude, hovered, zigzagged and sped
away. A second disc-shaped UFO, similar in outline, was
then seen hovering farther away. Finally, it tilted up
vertically and shot up out of sight.